Contact mechanism for circuit breakers



Feb. 9, 1954 F. DRIESCHER, JR 2,668,891

CONTACT MECHANISM FOR CIRCUIT BREAKERS Filed Nov. 4, 1952 INVENTOP Fri-'2 Dn scher, JT'.

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Patented Feb. 9, 1954 CONTACT -MECHANISM FOR CIRCUIT BREAKERS ,FritzDriescher, J13, Moosburg fiermany ApplicationiNovember 4, 1952,Seria1N0. 318,709

.Claims priority, a p ation German March 11, 19.52

6 Claims.

The present invention relates to contact mechanisms for circuitbreakers, and more particularly to mechanisms of this characterwhichincludean arcing chamber where an explosion accompanying theinterruption of a heavy-current may safely take place, in which anyburnirig of main contacts is avoided.

Gen "ally the invention comprises. a contact mechan m wh includes a pairof main contacts and a ir of auxiliary contacts which auxilia y con actsopen only after opening of main contacts has been completed, all'arcingta i g lace between the auxiliary contacts. ihe aux liary contacts areenclosed in an arcing or explosion chamber which is divided intocompartments the individual compartments being closed automatically asthe arcing between the at iary contacts progresses andthe arcing pathbecomes longer. Preferablythe con-- tacts and auxiliary contacts aredisposed within a unitary housing formed of suitable insulatingmaterial.

Among the objects of the invention, is the provision oi circuit breakercontact of this character in which all arcing accompanying theinterruption or" a heavy current takes place between a pair of auxiliarycontacts which, at the time of the current interruption, are en closedin a special arcing Or explosion chamber.

A further object of the inventiouis theprovision of a mechanism of thischaracter invvhich the explosion chamber is partitioned into individualcompartments.

Another object of the invention is the provision of means forautomatically closing off and isolating the individual compartments ofthe arcing chamber so that the arc is positively extinguished.

Still another object of theinvention-isthe provision of telescopicspring means for preventing the opening of the auxiliary contacts untilafter the main contacts have opened.

Other and further objects will become apparout upon reading thefollowing-specificationtogether with the accompanying drawing fforming apart hereof.

"Referring to the drawing, the single figure is a diagrammaticrepresentation of an embodiment of the invention illustratively shown asa sectional view in elevation.

In the drawing, a movable main contact !'is shaped as a pointed rodandis mcvablydisposed within a chamber 2 of a housing which is made ofsuitable insulating material. The movable contact I is shown inengagement with a stationary contact 3 indicated'by way of example ascontact springs disposed within the chamber 2.

Immediately beneath the main contact chamber 2 is an auxiliary contactchamber i in-which all arcing and any incidental explosionstake place.Movably disposed within 'the auxiliary contact pin 55 is held by anannular stationary spring 5,,thus requiring a predetermined minimumforce to effect withdrawal or" the head T of themovable contact pin fromengagement with the stationary annular contact spring 6. Other forms ofauxiliary stationary contact may be used instead of the annular contactspring ii, provided there is a predetermined m1" .mum force required toeffect disengagement or the movable auxiliarycontact from the stationaryauxiliary contact.

The auxiliary contact chamber s is provided with an intermediate wall 5which divides the contact chamber t into two compartments. The auxiliarycontact chamber i is also provided with an end wail The intermediateWall 3 has an aperture 8 therein and the end wall 5 has an aperture 9'therein through which the auxiliary contact pin 5 passes freely.

The auxiliary contact pin 5 is secured through a telescopic spring unitit to the main movable contact supporting member Ii. After apredetermined movement of the main movable contact supporting member Iitoward the left as viewed in the drawing, a sufficient force is producedby compression of the helical springs in the telescopic spring unit Itto eiifect disengagement of the movable auxiliary contact pin ii fromthe stationary annular auxiliary contact spring t.

Each of'the openings 8 andt' is provided with a self-closing flap l2and'i'd, respectively. When the auxiliary contacts it are closed, theflaps i2 andlt are in the-positions indicated in solid lines, and whenthe auxiliary contacts 5-5 open, the flaps I2 and idswing through thearcs indicated in dotted lines to close the apermres B and 9,respectively. Instead of the gravity actuated flaps 12 and It,positively controlled closure means maybe utilized, such as rotary gatesor doors, for example.

Th main contacts l.-i and the auxiliary contacts "5+6 are electricallyconnected in parallel.

The main movable contact supporting member II may be moved manually, orit may-be actuatedby any desired conventional and well known form ofcircuit breaker mechanism. This has-been i'llustratively indicated inthe drawing as'a vertically movable pin Hi which is moved downwardly totrip the breaker. Pin it engages a rotary-lever it which forces ahorizontal pin l6 to'the-right against a compression springl'l.

,Arod-lii is pivoted tohorizontal pin as and is mechanically arranged'toactuate the tripping mechanismcf the circuit breaker which is ofconventional construction and which has therefore been omitted from thedrawin In operation, upon tripping of the breaker, the maincontact-supporting member ii moves tothe left to the position indicatedin dotted lines. In moving to the left the main contacts l-3 openimmediately and a force tending to open the auxiliary contacts 5-6 isdeveloped by compression of the springs within the telescopic springunit Ill. The annular contact spring 6, however, holds the head I ofauxiliary movable contact pin 5 until suificient force is developedwithin the telescopic spring unit to efiect disengagement of the head 1from the annular spring 6. When this occurs, the auxiliary movablecontact pin 5 is snapped rapidly to the left, and as it is withdrawnsuccessively through the apertures 8 and 9' in the walls 8 and 9,respectively, the doors l2 and I3 swing to their closed positions.Closure of the doors I2 and I3 extinguishes the arc and seals off thearcing or explosion chamber 4, dividing it into two separate isolatedcompartments.

It should be noted that a plurality of arcing or explosion chambers maybe provided if desired, and that each such chamber may be divided intothree or more compartments instead of two, if this is deemed to bedesirable.

Having thus described my invention, it will be apparent to those skilledin the art that many changes and modifications may be made in thedetails thereof without departing from the scope of the invention asdefined in the appended claims.

I claim:

1. Circuit breaker mechanism of the class described, comprising: a mainstationary contact; a main movable contact engageable with said mainstationary contact; a main movable contact supporting member upon whichsaid main movable contact is supported; an apertured arcing chamber; anauxiliary stationary contact disposed within said arcing chamber; anauxiliary movable contact connected with said main movable contact andfreely movable through said aperture into and out of said arcing chamberfor engagement with said auxiliary stationary contact; closure meansresponsive to withdrawal of said movable auxiliary contact from saidarcing chamber for closing said aperture; and delaying means efiectiveduring the opening of said main contacts for causing said auxiliarycontacts to remain closed until after said main contacts have opened,said delaying means comprising spring means connecting said movable auxiliary contact to said supporting member, said two auxiliary contactsfurther comprising means for opposing the opening of said auxiliarycontacts until a predetermined minimum force tending to open saidauxiliary contacts has been produced in said spring means by movement ofsaid supporting member.

2. Contact mechanism according to claim 1, wherein said spring meanscomprises a telescopic spring unit.

3. Contact mechanism according to claim 1, wherein said means foropposing the opening of said auxiliary contacts comprises a head portionof one of said auxiliary contacts in engagement with an annular springportion of the other contact, said minimum force being required towithdraw said head from said annular spring.

4. Circuit breaker contact mechanism of the class described, comprising:a main stationary contact; a main movable contact engageable with saidmain stationary contact; an apertured arcing chamber; an auxiliarystationary contact disposed within said arcing chamber; an auxiliarymovable contact connected with said main movable contact and freelymovable through said aperture into and out of said arcing chamber forengagement with said auxiliary stationary contact; closure meansresponsive to withdrawal of said movable auxiliary contact from saidarcing chamber for closing said aperture; an apertured partition withinsaid arcing chamber dividing said chamber into a plurality ofcompartments, said movable auxiliary contact being freely movablethrough said partition aperture; closure means responsive to withdrawalof said movable auxiliary contact through said partition aperture toclose said aperture and isolate said compartments from each other; anddelaying means eifective during the opening of said main contacts forcausing said auxiliary contacts to remain closed until after said maincontacts have opened.

5. Circuit breaker contact mechanism of the class described, comprising:a main stationary contact; a main movable contact engageable with saidmain stationary contact; an apertured arcing chamber; an auxiliarystationary contact disposed within said arcing chamber; an auxiliarymovable contact connected with said main movable contact and freelymovable through said aperture into and out of said arcing chamber forengagement with said auxiliary stationary contact; a gravity actuatedflap responsive to withdrawal of said movable auxiliary contact fromsaid arcing chamber for closing said aperture; and delaying meanseffective during the opening of said main contacts for causing saidauxiliary contacts to remain closed until after said main contacts haveopened.

6. Circuit breaker contact mechanism of the class described, comprising:a main stationary contact; a main movable contact engageable with saidmain stationary contact; an apertured means effective during the openingof said main contacts for causing said auxiliary contacts to remainclosed until after said main contacts have opened, said delaying meanscomprising pring means effective after opening of said main contacts anddisposed to exert a force tending to open said auxiliary contacts, saidforce being sufficient to withdraw said head of said pin from saidannular spring.

FRITZ DRIESCI-IER, JR.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,393,344 Conrad Oct. 11, 1921 2,480,622 Warnock Aug. 30, 1949FOREIGN PATENTS Number Country Date 389,882 Great Britain Mar. 30, 1933430,452 Great Britain June 19, 1935

